Back in 2015, the Paris Agreement called for the creation of an international program through which countries could trade emissions to meet their climate commitments. For that to happen, the world has to agree on what qualifies for a carbon credit.

Most offset programs to date have focused on planting and preserving vast tracts of forests or wetlands. A few have a higher-tech focus, aiming to lock up carbon dioxide in rock or store it underground.

Now Bloomberg reports a UN group working on the issue has declared that engineering-based systems do not meet any of the objectives of the program—and might not even qualify for it. But nature-based programs have their issues, too, with some accused of being virtually worthless.

The debate is now in full swing in the lead up to COP28 Climate talks in November. No formal UN decision has yet been made. But when it is, it could profoundly affect how humanity can respond to the carbon removal challenge in the decades ahead. Here’s how the choices shape up.

• • •

(A) Cheap But Impermanent

1.  A forest of forest projects. There’s an affordable, scalable way to store gigatons of carbon and it’s already shading your home, feeding you fruit, and providing sustainable building materials for skyscrapers. The recent UN guidance notes that natural solutions have not only been proven safe, they also are already storing 200,000 times as much carbon each year as high-tech systems and are up to 100x cheaper.

That’s all fantastic, until centuries of carbon goes up in smoke. The recent wildfires in Alberta, Canada released at least 17 million tons of carbon, according to EU satellite data—and wildfires in North America’s boreal forests are expected to increase by at least 150 percent by 2050. There are similar longevity concerns with coastal “blue carbon” offsets and rising sea levels.

2.  Questions over benefits. The UN notes that healthy forests, coastlines and rural areas can generate significant sustainable development co-benefits. These include improving crop yields through better erosion control and soil fertility, recharging groundwater, conserving valuable biodiversity, reducing air pollution, controlling floods, and supporting socio-cultural activities.

But those benefits don’t always trickle down to the grassroots level. Talking to Yale360, Indigenous leader Levi Sucre Romero of Costa Rica decries “carbon cowboys” who “make a lot of false promises to the communities . . .We used to hear about blood diamonds; this is blood carbon.” Of $1.7 billion promised at COP 26 in Glasgow to help Indigenous communities pursue land rights and protect the carbon in their forests, only 7% has gone directly to Indigenous peoples and local communities, says Romero.

3.  The science of greenwashing. The growing appetite for carbon credits leaves room for unscrupulous operators. To count as a carbon credit, a program must store more carbon than would have been captured if nothing had been done. Unfortunately, that’s not always the case. For example, researchers from Vrije Universiteit Amsterdam examined 29 projects in the Brazilian Amazon and concluded that only 5 had resulted in any carbon reductions.

The best move forward, however, isn’t necessarily to walk away. A McKinsey report suggests improving projects with robust digital registration and verification tools, anti-money-laundering checks, and a single governance body to supervise participants and oversee the market. The UN program, although painfully slow to arrive, could fulfill some of these functions.

• • •

(B) Durable But Expensive

1.  Carbon removal for the 1%. No nature-based system, where carbon remains in the ecosystem, can make the same claims of permanence as technology that stores carbon deep underground on geological timescales. Engineering-based systems are inherently more predictable, both in terms of how much carbon they will store and for how long.

But they’re pricey. Forest projects can generate carbon credits for around $50/ton, reports the World Resources Institute, compared with $250 to over $600 for today’s direct air capture technologies.

2.  A development dilemma. Unproven engineering-based systems, says the UN, “pose unknown environmental and social risks, do not contribute to sustainable development, are not suitable for implementation in the developing countries, and do not contribute to reducing the global mitigation cost.”

Not everyone agrees. In an open letter to the UN standards group, 100 carbon removal experts from start-ups, nonprofits, and academia wrote: “We would be pleased to connect you with carbon removal leaders advancing projects in Kenya, Kiribati, India, Brazil, and other locations around the world where carbon dioxide removal is contributing directly to local and regional economic development.”

3.  Small but scaling fast. Technological solutions still have a long way to go to compete with the natural world. They currently sequester only about 100,000 tons of CO2 annually—less than would be saved by installing 30 wind turbines.

Proponents hope that, like solar power and EVs before them, removal technologies will ramp up quickly with money and research. The Carbon XPrize is a $100 million contest to reward gigaton operations (removing a billion tons of CO2). Its latest publication is a list of over 50 startups and organizations that have hit milestones or won interim awards towards that goal. It’s a great place to learn more about the latest and greatest ideas in carbon removal, from floating seaweed platforms to repurposing mining waste to store carbon in seawater.

• • •

(C) All of The Above

1.  No need to choose. In their open letter to the UN, carbon removal industry leaders disagreed with the idea of pitting nature-based against high-tech systems at all. “Virtually every carbon dioxide removal approach is a hybrid of nature and engineering,” they wrote. “Instead of labeling and enumerating individual pathways and approaches, [the UN should] define the criteria that a given project must demonstrate . . .and let science, innovation, and the market compete to deliver the solutions offering the greatest climate impact and other co-benefits.”

2.  A need for speed. And if carbon removal is going to start having an impact, it needs to scale really, really fast. By 2035, the world will need at least 30 to 40 times as many carbon credits as exist today, says consultancy firm Ernst and Young. That almost certainly means deploying every carbon removal system that’s practical in our race against the climate clock.

Top image: ©Anthropocene Magazine